This invention is direct to grain flow rate monitor and in particular to a monitor for measuring the amount of seed thrown out the back of a thresher with the straw and chaff.
In operating a combine thresher, it is important to minimize the amount of grain being lost out of the rear of the combine as it is thrown out along with the chaff and straw. A farmer attempts to minimize this grain loss by adjusting the thresher and controlling the forward speed for particular harvesting conditions so as to recover the highest percentage of grain possible. Grain flow rate monitors of the type described in U.S. Pat. No. 3,593,720 which issued to Botterill et al on July 20, 1971 and in U.S. Pat. No. 3,606,745 which issued to Girodat on Sept. 21, 1971, measure the amount of seed being lost out of the rear of a thresher, and therefore assist the farmer in determining the proper thresher adjustments and forward speed.
Though these monitors have been useful in reducing grain losses, particularly in the heavier cereal grains, such as wheat, barley, etc., they have been found to lack sensitivity in distinguishing between grain and chaff in many crops. This lack of sensitivity is particularly acute in the monitoring of oil seed grains such as rape and flax. These grains have very light seeds and sensitivity is lacking since both the seeds and the chaff are nearly equal in weight.